The China Open claimed its first high-profile victims on Sunday with Britain's Johanna Konta and Svetlana Kuznetsova of Russia falling to surprise defeats in the first round.
The sixth seed Konta, who reached last year's final, appeared woefully short of confidence in getting thrashed by Romania's unseeded Monica Niculescu 6-1, 6-2.
Konta exited soon after Kuznetsova – the seventh seed on the Beijing outdoor hard courts – was beaten by Lara Arruabarrena, the Spanish qualifier stunning her better-known opponent 6-7 (2/7), 7-5, 6-1.
Caroline Wozniacki had a fright against a local favourite before she composed herself to go through 6-1, 6-7 (4/7), 6-1.
The Dane, ranked six in the world, made an early exit from the Wuhan Open last week.
She appeared determined to put that behind her in making a lightning-fast start in the Chinese capital, punishing China's Wang Qiang in the first set.
But if the fifth seed thought she was going to have it easy, she was mistaken, as the 55th-ranked Wang harnessed the support of the crowd to fight back.
The 25-year-old Wang sprang a surprise in taking the second set on the tie break to level the match.
But former No 1 Wozniacki, the 2010 China Open champion, regained her poise to seal the deciding set with ease.
The 27-year-old faces Anastasia Pavlyuchenkova of Russia in round two.
Also through is reigning China Open champion Agnieszka Radwanska, who defeated the German qualifier Carina Witthoeft 7-5, 6-3.
"When you're defending so many points it's always a little more pressure," Radwanska said.
"There are no easy matches and you're going to have to play your best game from the first round. I'm very happy with a two-set win."